• Korean Journal of Ecology and Environment
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• v.42 no.4
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• pp.422-431
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• 2009

This study was to provide basic data for aquatic ecosystem research using fishes. Field sampling was carried out at five selected sites of Gap Stream, and fish samples, especially for a selection of sentinel species were collected three times in June, September, and October 2007. We analyzed total length distribution of Zacco platypus in relation with the season and the sampling sites, and then compared with total body weight, condition factor (K), and age distribution of the fish. The fish population data were compared with physico-chemical water quality, obtained from the Ministry of Environment, Korea. Water quality analysis showed a significant nutrient enrichment, based on total nitrogen (TN) and total phosphorus (TP), and organic matter pollution, based on biological oxygen demand (BOD) and chemical oxygen demand (COD) in the Site 5, which is directly influenced by wastewater disposal plant (WDP). Population analysis of the sentinel species showed that the total number of individuals, age distribution, and the population size-structure were influenced by the effluents from the WDP, and that reproductive failure of young-age population were evident in Site 5. According to the relation analysis of total weight to K, the disturbed population was mainly attributed to combined effects of habitat modifications and chemical degradations. Regression analysis of K values against water quality parameters showed significant (p<0.05) positive relations with nutrient and organic matter contents. Our data suggest that the population structure using a sentinel fish species reflected the ambient water quality in the stream and that diagnosis of aquatic ecosystem health using Z. platypus population may be practical for water resource and ecosystem conservations.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.6
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• pp.755-762
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• 2012

Qualities properties of fish sauce made jack mackerel (Trachurns japonicus) at different salt concentrations (25~35%) for 240 days at fermentation temperature ($25{\sim}55^{\circ}C$) were investigated. Total nitrogen content of the fish sauce made jack mackerel at 25% salt concentration after 240 day of fermentation was higher than those of 30%, 35% salt concentration. Total nitrogen content was increased under the same condition as fermentation temperature increased except at $55^{\circ}C$. Amino nitrogen contents at 25% salt concentration after 240 day of fermentation at 35, 45, $55^{\circ}C$ were 949.3, 812.8 and 834.4 mg/100 g, respectively. Those at 25, $55^{\circ}C$ fermentation temperature were 811.2 and 614.8 mg/100 g, respectively. The amino acid nitrogen content at 30 and 35% salt concentration ware lower than 20% salt concentration and that after 240 day of fermentation at $55^{\circ}C$ was lowest. The volatile basic nitrogen content increased during fermentation as fermentation temperature increased. However, increasing salt concentration controlled the formation of volatile basic nitrogen. Histamine content of samples fermented at $25{\sim}55^{\circ}C$ after 240 days were 9~20 mg/kg showing that it was not significantly different among salt concentration. The results indicated that the controlled salt concentration and fermentation temperature could be used as a successful process for fish sauce of jack mackerel as an unused resource.

• Journal of Ocean Engineering and Technology
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• v.21 no.5
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• pp.61-67
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• 2007

As part of the government's fishery resource creation policy, fishing ground creation projects have been undertaken in Korea's major seashore fishing spots since the 1970s, where artificial reefs constructed using new materials that make up for the weakness of concrete reefs have been used. In this study, the stability of these artificial reefs when acted upon by external forces, their ability to attract and gather fish, and their economic feasibility were examined. For this purpose, an experimental artificial steel reef was constructed and was installed in an area of the sea. Then the corrosion of the experimental material attached to it was investigated. The efficiency of the artificial steel reef was then verified by examining its functionality, removal, and burying, as well as the speed of insertion of living things into its structure and its ability to attract and gather fish.

• Animal cells and systems
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• v.16 no.4
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• pp.343-349
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• 2012

A variety of fish species undergo an ontogenetic change in prey selectivity, and several potentially interacting factors, including nutrient requirement, microhabitat change, and foraging ability, may account for the occurrence of the shift. Here we examine the foraging ecology and ontogenetic diet shift of a micro-carnivorous goby, Pterogobius elapoides (serpentine goby), dominant component of fish assemblage in shallow rocky areas off the coast in Korea and Japan. Although most other gobies are primarily benthic carnivores, P. elapoides is a semipelagic fish; however, little is known about how those species change their foraging tactics with growth. In our diet analyses, the most common diet was pelagic copepods and benthic amphipods, and diet shift was observed from pelagic to benthic with growth. The ontogenetic diet shift seems to be the result of the preference for energetically more profitable prey in larger-size classes as well as the results of different prey availability due to among-habitat variation in diet. However, differential food preference does not appear to affect individual scope for searching food. Several factors such as predation pressures and interspecific resource partitioning might contribute to the changes in diet observed among size classes, which were included in our ongoing tests.

• Fisheries and Aquatic Sciences
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• v.27 no.8
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• pp.475-487
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• 2024

Larviculture of commercially important aquaculture species faced limitations associated to the incomplete understanding of larval nutrition and the inability to total replacement of live feeds by formulated diets at the early larval stage. The main challenges to alternatives of live feed in larval fish culture are related to the inherent behaviors of the larvae and the incomplete knowledge and practice leading to the inefficiency of using micro diets. Although significant achievement has been reached in the complete replacement of live feeds by formulated micro diets in freshwater species and marine shrimps, its success is far from complete in marine finfishes. However, recent progress in biotechnological advances in manufacturing process and advanced knowledge of the nutritional necessities of larvae indicated improvements in the field. A range of technologies in the manufacturing of micro diets for larval fish are in place currently. To this end, several achievements of substituting live feeds with formulated micro diets at later stages of larval development have been reported by various researchers providing a clue on the prospects for the future. Therefore, the objective of this review is to compile existing information on the challenges of substituting live feeds by formulated diets in the past and prospects for future development.

• Journal of fish pathology
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• v.24 no.1
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• pp.19-27
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• 2011

The production of surf clam, Mactra veneriformis, an important fishery resource in Korea, has recently been decreasing. This study was carried out to examine effects of spawning on immune functions of this species. Total hemocyte count (THC), phenoloxidase (PO) activity, phagocytic activity, neutral red retention (NRR) time and antibacterial activity were assessed. Spawned clams showed reduction in THC, PO, phagocytic activity and NRR times compared with unspawned ones. While spawning event did not elicit any change of antibacterial activity in both spawned and unspawned ones. This study indicates that spawning process decreases immune functions in the surf clams which could cause mortality increment and yield reduction.

• Korean Journal of Ichthyology
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• v.21 no.sup1
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• pp.52-62
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• 2009

Environmental differences of each sea around the Korean Peninsula in terms of factors including topography and complexity of sea current may influence species and genetic diversity of marine fishes. Fish are naturally abundant in the frontal area where various currents or water masses meet. However, this food resource is prone to human overexploitation, threatening the marine ecosystem. New fisheries resources management strategies are needed. Such strategies require information about population structure obtained through morphological and genetic methods.

• Genomics & Informatics
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• v.18 no.3
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• pp.32.1-32.7
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• 2020

The mitochondrial genome of a species is an essential resource for its effective conservation and phylogenetic studies. In this article, we present sequencing and characterization of the complete mitochondrial genome of a threatened labeonine fish, Cirrhinus reba collected from Khulna region of Bangladesh. The complete mitochondrial genome was 16,597 bp in size, which formed a circular double-stranded DNA molecule containing a total of 37 mitochondrial genes (13 protein-coding genes, 2 ribosomal RNA genes, and 22 transfer RNA genes) with two non-coding regions, an origin of light strand replication (OL) and a displacement loop (D-loop), similar structure with other fishes of Teleostei. The phylogenetic tree demonstrated its close relationship with labeonine fishes. The complete mitogenome of Cirrhinus reba (GenBank no. MN862482) showed 99.96% identity to another haplotype of Cirrhinus reba (AP013325), followed by 90.18% identity with Labeo bata (AP011198).

• Korean Journal of Ecology and Environment
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• v.45 no.4
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• pp.482-489
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• 2012

Visual monitoring is hard to apply on fish because they are living in a water system. To overcome this problem, acoustic telemetry, which is effective for underwater monitoring, is often used for studying fish behaviors, such as movement distance, route and patterns. In this study, in order to monitor the movement pattern of Squaliobarbus curriculus (family Cyprinidae), we used acoustic telemetry and identified the home range and movement distances. A total of nine individuals were released at two different locations: one is at the estuary barrage (Sc1~3) and the other is at the lower part of Baekjae Weir (Sc4~9), located in Geum River. Approximately, a 70 km section from the estuary barrage was investigated. Fish, which were released at the estuary barrage, utilized up to 12.7 km upstream as home range from the release site. At the lower part of Baekjae Weir, most of the fish moved and stayed within a 7.2 km downstream area, except for Sc6, which moved 53.4 km (linear maximum distance from release site) downstream from the release site. Relatively small sized fish (Sc7~9) did not show any movement. Accumulated movement distance significantly correlated with the standard length of S. curriculus ($r_s$=0.715, p=0.03). Moreover, the standard length of moving fish was significantly larger than that of not moving fish (Mann-Whitney U test, p=0.024). Therefore, the movement distance of S. curriculus has been correlated with fish size; movement distance was increased with the standard fish length. Although the sample size of monitored fish was small, various meaningful data were collected by acoustic telemetry. Consequently, this technique could be a method available for effectively monitoring the behavior and ecology of native Korean and endemic species.

• The Journal of Fisheries Business Administration
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• v.29 no.2
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• pp.111-141
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• 1998

Why are auctions so prevalent in fisheries fields\ulcorner One answer is, perhaps, that fisheries products have no standard value. The price of any catch of fish (at least of fish destined for the fresh fish market) depends on the demand and supply conditions at a specific moment of time, influenced by prospective market developments and prices must be remade for each transaction. There are various auction schemes including written-bid method in Korea. It is difficult to make decision the application of auction selling in market distribution. One reason is the absence of adequate data on which to base firm statements. There is very little precise information about the relative volume handled by auction scheme as compared with other sales schemes Because of the paucity reliable data, one must depend largely on qualitative in attempting to above this problem. This paper is designed to examine which auction scheme is more efficient as a economic tool by introducing the three auctions, as samples, utilized in Koheung peninsula. Koheung coast with abundant fisheries resource, locates on the Middle-South part in Korea and has three auction firm operating by fisheries cooperatives. fur selling of dry fish included sea weed, live fish and fresh fish respectively, As a result, 1 found that there are three interesting auction schemes as follow : 1. More than one winners are selected as buyers. The highest bidder can at first get fishes he wants to buy, second winner can get surplus fishes after the highest bidder employes one's privilege with the highest pay, and next winner would be a buyer if fishes would be left in sequence after being sold with higher price. Every fisherman can sell one' s fishes with equal unit price if he delivery it to the winner within one day. Therefore, all the vendors feel they are equal members of fisheries cooperation. 2. Written-bid pricing on the cover of handy book. It is easy to write and to erase the figure more than on the small black board, and is convenient also to keep in the pocket. 3. Auctioning on the fixed platform with fixed fish tank is a very fast auction scheme in spite of short displaying time. Auctioneer presides bidding at one place on the fixed platform, instead of moving, vendors should carry a container of live fishes in the fish tank into showing table in front of would-be buyers and auctioneer. Although the applicability of the auction system to a marketing problem depends in part on subjective considerations by those making decision, basically it is a matter of comparative economic efficiency. In general, if the scheme maximizes returns in relation to the effort expanded by both buyers and sellers, it will be utilized. If it does not, a more efficiency may take place over a period of time, but, even more important, those making decisions may become aware of the potentialities of new schemes. Therefore, in order to applicate the three interesting auction schemes introduced in this paper to other fisheries market, it is necessary not only to analyze many other auction schemes but also to compare the economic efficiency those schemes utilizing in other fisheries market.